Graded Browser Support Update

By YUI TeamJuly 3rd, 2008

Updated July 8th: The chart below has been corrected to include Safari 3.1†, replacing Safari 3.0†.

This post announces an update to Graded Browser Support. The GBS page on the YUI site always has the most current information. This post includes a list of primary changes, the updated chart of browsers that receive A-grade support, the GBS forecast, and notes specific to the YUI Library.

Primary Changes

These changes are included in this update.

  • A-grade support for Firefox 3 begins.
  • A-grade support for Firefox 2 is reduced to Win XP and Mac 10.5.
  • A-grade support for Opera 9.5 begins on Win XP and Mac 10.5.
  • A-grade support for Win 98 is discontinued, as previously forecast.
Win 2000 Win XP Win Vista Mac 10.4 Mac 10.5
Firefox 3.† A-grade A-grade A-grade A-grade A-grade
Firefox 2.† A-grade A-grade
IE 7.0 A-grade A-grade
IE 6.0 A-grade A-grade
Opera 9.5† A-grade A-grade
Safari 3.1† A-grade A-grade

The dagger symbol (as in “Firefox 3.†”) indicates that the most-current non-beta version at that branch level receives support. Put another way, † means “the most recent” instead of “all.”

GBS Forecast

In addition to the effective-immediately changes, we’re keeping our eyes on pending developments.

  • Internet Explorer 8

    GBS does not extend A-grade support to beta versions of browsers. (They receive X-grade support by definition.) However, it’s important to be aware of forthcoming releases, especially from established brands that enjoy rapid adoption once generally available (GA). We are currently watching the development progress of Internet Explorer 8.

    We made an exception to our “no-betas” stance during IE7’s beta phase in recognition of IE’s market share and ability to promote rapid adoption. The exception — committing development and QA resources to provide A-Grade prior to a GA release — gives us an opportunity to learn the new browser’s quirks and provide feedback while it is still being developed. And it means our sites are prepared when it goes GA. We will likely extend the same accommodation to IE8. Stay tuned.

Notes Specific to the YUI Library

  • YUI version 2.5.2

    YUI 2.5.2, released May 28, 2008, includes full support for Firefox 3.0 and Opera 9.5, even though those two browsers were just added to GBS in this update.


  1. A long time ago the table for GBS showed C-grade and X-grade browsers. Is there a more comprehensive list available somewhere?

    I’ve always thought the Yahoo! GBS concept is reasonable guide when thinking about the browser version problem but I don’t remember seeing its manifestation in code. I haven’t looked in detail in the YUI libraries for a while but I don’t remember any code in the libraries that helped developers ensure that C-grade browsers would receive a C-grade experience. Something like feature testing required features before defining a widget. Is there something I missed on how Yahoo! implements this philosophy?

  2. Hey Peter,

    In the past, the slots on the A-grade chart that happened to be C-grade were marked as such. But that gave an incomplete picture of the C-grade membership (Lynx isn’t in the chart, for instance), so I removed it.

    You’re right that a technology piece is missing. It’s in the works. Stay tuned…


  3. What should I answer my bosses, if they tell me: “We won’t use YUI, because it is not tested on Linux.”?

    Do your developers use Linux and could this be counted as a kind of test? Or is it sure, that it will work on Linux, if it also works on Mac and Win?

    Could you add a comment about Linux to the browser support page that helps me to advocate for Linux?


  4. Sorry: To advocate for YUI, I mean. :-)

  5. How about support for GNU/Linux browsers? I’d expect FF in this overview… ?

  6. Hi,

    We use a similar chart based on a mixture of this and the BBC’s version.

    I’m interested in the decision to continue support for FF2 in Windows XP but not Vista. Could you explain the thinking there?


  7. @Thomas, @Tonci,

    As the documentation for GBS says, “The only practical difference between A- and X-grade browsers is that QA actively tests against A-grade browsers.” Mozilla ensures that Firefox is highly consistent across various operating systems; we ensure that the YUI experience on Firefox on the platforms used most by our users is highly consistent. Following the GBS approach, we therefore trust that a solid experience in A-grade environments will also provide a solid experience in X-grade environments.

    If you find cases where this is not true, please be sure to report them for analysis.

    Please also read my response to a similar question from an earlier post.

    Hope that helps.


  8. @David,

    First, while many people have updated to Firefox 3, there are still many Firefox 2 users. So I think it’s important to continue to provide some test coverage for the Firefox 2 branch.

    Second, each instance of A-grade support is expensive in terms of resources, because we run comprehensive tests on each instance. Therefore, reducing instances is beneficial.

    Since Mozilla strives for cross-OS consistence, I’m more concerned with testing the FF2 branch as a branch instead of each OS instance of that branch.

    The compromise I arrived at was to provide A-grade support to the Firefox 2 branch on one Windows and one Mac OS instance.

    Make sense? Suggestions? Comments?


  9. [...] Browser compatibilità [...]

  10. Nate,

    Interesting about your compromise for FF2. I had wondered the same thing. Do you have a budget for the number of A-grade green boxes you are allowed in the table?


  11. Why was the choice made for Yahoo to extend A-grade support to Safari 3.0 on Mac and not to 3.1 or to Safari on Windows?

    Could you also provide a list of what Yahoo extends C-grade support to separate from the chart?

  12. Re: the GNU/Linux comments — I develop using Firefox on Ubuntu and YUI 2.5.1 and I’ve never had any problems. Makes sense that you’d like more official support but I thought I’d throw that out there.

  13. [...] Yahoo! has upgraded their browser support gradings. From the Yahoo! User Interface Blog: [...]

  14. @Peter – No budget, but I try to maintain empathy for all my developer and tester friends.

    @Chris – C-grade chart is in the works. Safari on Windows receives X-grade support. Safari will be 3.1 shortly.

    @Matt – thanks for the testimonial. That’s been my experience as well.

  15. Note that the chart has been corrected to include Safari 3.1†, replacing Safari 3.0†. Sorry for the inconvenience.


  16. Ben Glancy said:
    July 4, 2010 at 8:29 am

    I use Ubuntu Linux with Firefox and find that the Yahoo uploader does not work, the “select files” link is covered up by a grey square and no dialog appears when you click it.

    Everysooften it says “adobe flash has crashed”.